The present invention relates generally to semiconductor packages, and more specifically, to a method for connecting a semiconductor die to a substrate in semiconductor packages.
Various techniques are used for establishing an electrical connection between a semiconductor die and a substrate in a semiconductor package. One such technique is wirebonding, in which the semiconductor die is initially attached to a lead frame or a substrate. Thereafter, a gold or copper wire is used to form an interconnection between the semiconductor die and the substrate or the lead frame. However, wirebonding is an expensive process due to the high cost associated with the wires.
Wafer bumping, also known as solder bumping, is another known technique used for electrically connecting a semiconductor die to a substrate or a carrier, in flip-chip packaging. In wafer bumping, solder bumps are formed over bond pads of the semiconductor die. Thereafter, the substrate is placed over the semiconductor die such that the bond pads of the substrate are aligned with the bond pads of the die. Subsequently, the package is heated so that the solder bumps form an electrical connection between the semiconductor die and the substrate. However, wafer bumping process is also costly and time-consuming. It would be advantageous to be able to attach and electrically connect a die to a substrate with an inexpensive yet reliable process.